Registration metrology tool using darkfield and phase contrast imaging

ABSTRACT

The present disclosure is directed to an inspection system for registration metrology and defect detection using darkfield and phase contrast imaging optical systems. The present system includes a transmitted light mode and diffracted light mode to enable imaging of low contrast features on blank EUV masks and semiconductor wafers. In an aspect, this system combines the optics for darkfield and phase contrast imaging, and may also include the optics for brightfield imaging, to provide analyzed data on registration errors and surface defects.

BACKGROUND

For advanced semiconductor devices, a single layer mask exposure andetch are no longer sufficient to meet the required pattern density. As aconsequence, the number of masks required to produce an integratedcircuit has increased. The required patterns need to be split up anddivided over multiple masks. With the increasing number of masksrequired to produce a semiconductor device, there have been commensurateconstraints on the mask-to-mask on-product overlay requirements,controls, and inspections as well.

Before a mask is patterned and especially after the mask is patterned,the mask must undergo inspections and metrology. There are oftenstringent on-product overlay specifications (<3-nm) required forintra-layer (e.g., multi Litho Etch (LEn) and Spacer AssistedDouble/Quadruple Patterning (SADP/SAQP)) overlay performance as well asfor inter-layer to layer overlay. To keep the on-product overlay withinsemiconductor device specification over time, the number of on-waferoverlay metrology steps inside the fab has increased. It would bebeneficial to fully characterize the mask-to-mask overlay off-line andapply overlay techniques to improve the on-wafer overlay.

There are off-line metrology inspection techniques that address andreduce the overall wafer/lot cycle time inside the fab. However, currentinspection techniques, for example, for detecting defects in extremeultraviolet (EUV) blanks rely on actinic inspection, which may reducemask lifetime. The widely used 193 nm optical inspection tools may betypically equipped with bright field imaging optics for reflection ortransmission mode measurements. Such broadband brightfield imagingminimizes contrast variations and coherent noise and is not sensitive tosmall features and particles. These measurements work well for largefeatures within the 10-micron range, but for process technology forsmaller nodes, the next generation alignment marks may result in lowerimage contrast when using brightfield illumination.

There is a growing use of EUV-based phase shift masks and it would bebeneficial to minimize the number of steps used in mask processing toreduce the impact on EUV photomasks. In particular, EUV phase photomasksmay benefit from the use of phase contrast based alignment marks forpattern registartion and overlay in view of the extreme sensitivity ofEUV light to phase changes down to a single atomic layer of a phaseabsorber.

It is understood that inspection and metrology are the key parts of thesemiconductor manufacturing process flow, because, if there is a defectof a problem on the mask, it will get printed on the final wafer. As aconsequence, however, the increasing number of metrology steps mayresult in a negative impact on the overall wafer/lot cycle time in thefab. Accordingly, the manufacturing processes for semiconductor devicesmay benefit from improved techniques and systems for off-linemask-to-mask registration metrology and inspections; in particular, forEUV blank masks.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameparts throughout the different views. The drawings are not necessarilyto scale, emphasis instead generally being placed upon illustrating theprinciples of the present disclosure. The dimensions of the variousfeatures or elements may be arbitrarily expanded or reduced for clarity.In the following description, various aspects of the present disclosureare described with reference to the following drawings, in which:

FIG. 1 shows a block diagram of an exemplary inspection/metrology systemaccording to an aspect of the present disclosure;

FIG. 2 shows a schematic diagram of an exemplary optical train accordingto an aspect of the present disclosure;

FIG. 3 shows a schematic diagram of another exemplary optical trainaccording to another aspect of the present disclosure;

FIG. 4 shows a schematic diagram of yet another exemplary optical trainaccording to another aspect of the present disclosure;

FIG. 5 shows a schematic diagram of a further exemplary optical trainaccording to further aspects of the present disclosure;

FIG. 6 shows an exemplary laser interferometer system according to anaspect of the present disclosure;

FIGS. 7A, 7B, and 7C show diagrams of exemplary optical subcomponentsaccording to an aspect of the present disclosure; and

FIG. 8 shows a simplified flow diagram for an exemplary method accordingto an aspect of the present disclosure.

DETAILED DESCRIPTION

The following detailed description refers to the accompanying drawingsthat show, by way of illustration, specific details, and aspects inwhich the present disclosure may be practiced. These aspects aredescribed in sufficient detail to enable those skilled in the art topractice the present disclosure. Various aspects are provided fordevices, and various aspects are provided for methods. It will beunderstood that the basic properties of the devices also hold for themethods and vice versa. Other aspects may be utilized and structural,and logical changes may be made without departing from the scope of thepresent disclosure. The various aspects are not necessarily mutuallyexclusive, as some aspects can be combined with one or more otheraspects to form new aspects.

Presently, conventional inspection tools may not be capable ofidentifying low-contrast EUV fiducial marks to correctly perform imageprocessing to detect edges of features used for alignment and overlay inmask manufacturing, Low contrast phase defects or alignment marks aredifficult to capture on brightfield imaging inspection tools and using13.5 nm actinic inspection for alignment marks has concerns relating todegradation and mask lifetime. According to the present disclosure, thepresently used brightfield imaging inspection tools with 193 nm lasersmay be provided with darkfield illumination optics and/or phase contrastoptics to expand the capability of these tools.

The present disclosure is directed to an inspection method that providesa semiconductor specimen with a stage for inspection and a light sourceto produce illumination that passes through a first optical trainconfigured with phase contrast optical components to focus phasecontrast illumination toward one or more features of the semiconductorspecimen, and sensing the phase contrast illumination from the one ormore features of the semiconductor specimen using a first charge-coupleddevice (CCD) sensor, and provides illumination through a second opticaltrain configured with darkfield optical components to focus darkfieldillumination toward the one or more features of the semiconductorspecimen, and sensing the darkfield illumination from the one or morefeatures of the semiconductor specimen using a second CCD sensor,provides position measurements using an laser interferometer, andgenerates analyzed data for the one or more features of thesemiconductor specimen from data captured by the first and second CCDsensors and laser interferometer using a computing device.

In addition, the method may further include providing illuminationthrough a third optical train configured with brightfield opticalcomponents to focus brightfield illumination toward the one or morefeatures of the semiconductor specimen and sensing the fieldillumination from the one or more features of the semiconductor specimenusing a third CCD sensor, and for which the analyzed data for the one ormore features of the semiconductor specimen includes data captured bythe third CCD sensor.

The present disclosure is also directed to an inspection system thatincludes an optical inspection tool having a stage, a light source, afirst optical train configured with phase contrast optical components, asecond optical train configured with darkfield optical components, andat least one CCD sensor configured to sense illumination directed from asemiconductor specimen, a laser interferometer, and a computing device.In addition, the inspection system may further include a third opticaltrain configured with brightfield optical components.

The present disclosure is directed to an optical inspection toolincluding a stage, a deep ultraviolet laser emitting 193-nanometerwavelength illumination, and a multi-mode optical system including afirst optical train configured with phase contrast optical components, asecond optical train configured with darkfield optical components, and athird optical train configured with brightfield optical components, andat least one CCD sensor configured to sense illumination directed from asemiconductor specimen.

In addition, the present multi-mode optical system may further include abrightfield optical inspection tool that is retrofitted with phasecontrast optical components, darkfield optical components, and phasecontrast and darkfield CCD sensors.

It is understood that darkfield imaging collects scattered light from adefect, while brightfield imaging collects reflected light. Small,transparent defects may scatter efficiently in darkfield illuminationbut may be very difficult, if not impossible, to detect in brightfield.Darkfield imaging is generally useful in detecting defects having aspecific height, depending upon the interaction between illuminationwith the geometry and effects due to transparent layers on the specimen.

By incorporating darkfield optics and phase contract optics (such asSchwarzschild's Optics and Zernike Phase Contrast optics), according tothe present disclosure, it is possible to detect smaller phase defectswithin a multi-layer stack of a blank EUV mask and lower (poor) contrastEUV alignment marks using a 193 nm excitation source.

To more readily understand and put into practical effect, the presentregistration metrology tool using brightfield, darkfield and phasecontrast imaging, and methods which may be used for inspectingsemiconductor specimens, such as blank EUV masks and semiconductorwafer, particular aspects will now be described by way of examplesprovided in the drawings that are not intended as limitations. Theadvantages and features of the aspects herein disclosed will be apparentthrough reference to the following descriptions relating to theaccompanying drawings. Furthermore, it is to be understood that thefeatures of the various aspects described herein are not mutuallyexclusive and can exist in various combinations and permutations. Forthe sake of brevity, duplicate descriptions of features and propertiesmay be omitted.

In FIG. 1 , according to an aspect of the present disclosure, aninspection system 100 is shown. The present inspection system 100 mayinclude an optical microscope tool (not shown) used to inspect a mask orwafer 101, which may have a registration feature 102 (or a defect). Inan aspect, the mask or wafer 101, as a device under test or DUT, may bepositioned on a stage or platform 103 for illumination by inspectionsystem optical components 104 (i.e., darkfield, phase contrast andbrightfield optical components, and a single or multiple light sources).In an aspect, the light source (not shown) may be a laser with a 193 nmwavelength. The present inspection system 100 may be one or more imagesensors, which are shown as charge-coupled device (CCD) detector/camera105 a (used in reflected light mode) and CCD detector/camera 105 b (usedin transmitted light mode).

In another aspect shown in FIG. 1 , a laser interferometer system 106may be provided for the present inspection system 100 to generatepositional/location data. An exemplary laser interferometer is describedin FIG. 6 below.

In yet another aspect, the various subsystem of the present inspectionsystem 100 may be coupled to a processor or computing device 110, whichmay include a control unit 107 a measurement data analyzer 108, and adata storage/capture unit 109, and generate analyzed data (e.g.,registration data) as an output signal 111. It is within the scope ofthe present disclosure to provide the processor 110 as an integratedunit, or as a standalone computing device or workstation. In addition,the data storage unit 109 may provide idealized images for standardblank EUV masks and/or semiconductor wafers that may be used forcomparison with the measured data.

In addition, it is within the scope of the present disclosure to haveincorporated other functional units as part of the present inspectionsystem; for example, a design data generation unit, a data convertingunit, an inspection data capture unit, an inspection data correctingunit, an image converting unit, a position accuracy measuring unit, ameasurement results obtaining/capturing unit, a defect storing unit, animage obtaining unit, an auto-focus unit, etc.

In an aspect, according to the present disclosure, the inspection system100 may use software with pre-programmed patterns for the scanning ofsurfaces of a mask or wafer, which may be stored in the data storageunit 109 or remotely in a server (not shown). The use of pre-programmedpatterns may permit the scans to be performed in an automated processand provide for generating selective scans of greater or lesser detailsas needed. In an aspect, a control software may be used to control theoperations and movements of the inspection system (e.g., movement of thestage 103 in the x-direction, y-direction, and z-direction, focusing ofthe microscope, etc). In another aspect, the present inspection system100 may employ image analysis software for analyzing the captured dataand generating data output and maps.

In yet another aspect, the present inspection system 100 may include auser interface (not shown) to provide inputs to the inspection system toinitiate automated scans, for modifying the automated scans, formanually scanning of a mask or wafer, etc.

It is within the scope of the present inspection system 100 of FIG. 1 toperform full processing of a blank EUV mask or wafer using varioussequences for combining darkfield imaging and phase contrast imagingand/or combining darkfield imaging, phase contrast imaging, andbrightfield imaging, i.e., either simultaneously or sequentially. In anaspect, an inspection may be performed by first obtaining registrationinformation using the brightfield imaging and using the data from thedarkfield and/or phase contrast imaging to correlate/correct anyregistration errors to improve the accuracy of the analyzed data and thegenerated output map. In situations when a brightfield image is notviable, then the darkfield image and/or phase image may be relied solelyto locate the center of the registration alignment marks.

FIG. 2 shows a schematic diagram of an exemplary optical train 200 thatmay be used with the present inspection system according to an aspect ofthe present disclosure. As shown, a semiconductor specimen or DUT 201may have a registration mark or defect 202 with illumination impingingon and/or passing through a condenser lens 203, a light annular detector204, an objective lens 205, and a scanning phase ring 206, and there maybe an image 207 or light source 209 depending on the operationaldirection. In an aspect, the present optical train 200 may provide, whenoperational viewed from left to right (i.e., in direction a), a“full-field” Zernike phase contrast imaging may be obtained. In anotheraspect, the present optical train 200 may provide, when operationalviewed from right to left (i.e., in direction b), a “scanning” Zernikephase contrast imaging. The present inspection system may use opticaltrain 200 for microscopes that are configured according to the presentdisclosure since they are mathematically equivalent and produce the sameimages if the optics angles θ and a shown in FIG. 2 are the same.

FIG. 3 shows a schematic diagram of another exemplary optical train 300that may be used with the present inspection system according to anotheraspect of the present disclosure. In an aspect, a light source 309 mayprovide illumination that passes through an annular aperture 303 and acondenser lens 304 to impinge on and/or pass through specimen 301 with aregistration mark or defect 302. Thereafter, as shown in FIG. 3 , fromthe illumination, undiffracted light “a” (solid) and diffracted light b(dashed) may be produced that are directed to and collected by anobjective lens 305. In an aspect, there will be interference between theundiffracted and diffracted light and their phase shifted by a phasering 306, which translates into phase variations, i.e., intensitymodulations in the image plane 307.

It will be understood that the most important concept underlying thedesign of a phase contrast microscope for the present inspection systemis the segregation of surround and diffracted wavefronts emerging from aspecimen, which are projected onto different locations in an objectivepositioned near a rear focal plane. In addition, the amplitude of thesurround (undiffracted) light must be reduced by a phase ring or plate,and the phase advanced or retarded (by a quarter wavelength by thespecimen) in order to maximize differences in intensity between thespecimen and background in the image plane.

FIG. 4 shows a schematic diagram of a further exemplary optical train400 that may be used with the present inspection system according tofurther aspects of the present disclosure. In FIG. 4 , the optical train400 may be provided for phase contrast imaging of a semiconductorspecimen 401 and may include illumination from a light source(non-polarized) 402 that follows a path through a polarizer 403, aquarter waveplate 404, an objective prism 405, a condenser 406, passingthrough the semiconductor specimen 401 and continuing through to anobjective 407, a nosepiece prism 408 and an analyzer 409. In thisaspect, the path of the illumination may be “dual channel” as it passesthrough the semiconductor specimen 401, which may preferably have equalintensity as they impinge on the specimen surface. The objective prism405 may divide the illumination into first and second channels.

FIG. 5 shows a schematic diagram of yet another exemplary optical train500 that may be used with the present inspection system according toanother aspect of the present disclosure. In this aspect, the opticaltrain 500 may employ Schwarzschild optics for darkfield imaging of asemiconductor specimen 501 having a registration mark or defect 502.Schwarzschild objectives are increasingly used in the EUV spectralregion as imaging optics because of their large aperture, highmechanical stability, and freedom from chromatic aberrations.

As shown in FIG. 5 , a light source 509 may provide illuminationdirected to a collector 503, with a central aperture 504 blocking acentral portion of the illumination (aka the zeroth order mode of thelight). The unblocked portion (aka first order and higher order mode oflight) of the illumination may be further directed to a condenser 505,which, in turn, directs it to the semiconductor specimen 501. Theundiffracted illumination may be blocked by an objective aperture 506,while the diffracted lamination may be refocused by an objective 507 anddirected to a darkfield image plane 508.

In FIG. 6 , an exemplary laser interferometer system 607 according to anaspect of the present disclosure is shown. The laser interferometersystem 607 may provide highly accurate measurements of the movements ofa stage 603, which supports a semiconductor specimen 601, that may bedirected by a precision motion control device (not shown). In an aspect,the laser interferometer measurements may be positioned near a stage'swork point to act as a feedback mechanism for the precision motioncontrol device. In an aspect, the data from a laser interferometersystem may be combined with optical data from brightfield, darkfield,and phase contrast images to provide information relating toregistration errors and/or defects.

FIGS. 7A, 7B, and 7C show diagrams of exemplary optics subcomponents forphase contrast illumination according to an aspect of the presentdisclosure. In FIG. 7A, exemplary objectives apertures are shown. InFIG. 7B, exemplary condenser annuluses are shown. In FIG. 7C, exemplarynegative and positive phase plates are shown. These opticalsubcomponents may be used to provide the phase shifting needed for phasecontrast illumination.

In a further aspect, to potentially perform a retrofit of a typicalinspection/registration metrology tool, it may be possible to convert abrightfield microscope for phase contrast observation by, among otherthings, providing a specially designed annular diaphragm, which ismatched in diameter and optically conjugate to an internal phase plateresiding in the objective rear focal plane that is placed in thecondenser front focal plane. For darkfield imaging, a brightfieldbeamsplitter may need to be removed and preferably replaced with ablank, or glass, when performing darkfield illumination, which allowsmore light to pass to a sensor and permits greater levels of detectionin darkfield imaging. An alternative method for producing the sameresult is to perform brightfield imaging in a selected wavelength oflight (e.g., 13.5 nm EUV light source, 193 nm ArF Excimer laser or 266nm, etc) or perform darkfield imaging in a different frequency lightspectrum (e.g., 355 nm 532 nm, 1064 nm which are harmonics of a Nd:YAGlaser).

FIG. 8 shows a simplified flow diagram for an exemplary method accordingto an aspect of the present inspection system.

The operation 801 may be directed to providing a semiconductor specimenon a stage.

The operation 802 may be directed to providing phase contrastillumination toward one or more features of a semiconductor specimen.

The operation 803 may be directed to providing darkfield illuminationtoward the one or more features of the semiconductor specimen.

The operation 804 may be directed to providing brightfield illuminationtoward the one or more features of the semiconductor specimen.

The operation 805 may be directed to analyzing data relating to the oneor more features of the semiconductor specimen.

The operation 806 may be directed to producing a combined phasecontrast, darkfield, and brightfield representation of the data for theone or more features of the semiconductor specimen as a defect map oralignment mark map.

It will be understood that any property described herein for a specifictool may also hold for any tool or system described herein. It will alsobe understood that any property described herein for a specific methodmay hold for any of the methods described herein. Furthermore, it willbe understood that for any tool, system, or method described herein, notnecessarily all the components or operations described will be enclosedin the tool, system, or method, but only some (but not all) componentsor operations may be enclosed.

To more readily understand and put into practical effect the presentmetrology system and methods for their use in gap measurements, theywill now be described by way of examples. For the sake of brevity,duplicate descriptions of features and properties may be omitted.

EXAMPLES

Example 1 provides an inspection method that includes providing asemiconductor specimen on a stage for inspection, providing a lightsource to produce illumination, providing illumination through a firstoptical train configured with phase contrast optical components to focusphase contrast illumination toward one or more features of thesemiconductor specimen, and sensing the phase contrast illumination fromthe one or more features of the semiconductor specimen using a firstcharge-coupled device (CCD) sensor, providing illumination through asecond optical train configured with darkfield optical components tofocus darkfield illumination toward the one or more features of thesemiconductor specimen, and sensing the darkfield illumination from theone or more features of the semiconductor specimen using a second CCDsensor, providing position measurements using an laser interferometer,and generating analyzed data for the one or more features of thesemiconductor specimen from data captured by the first and second CCDsensors and laser interferometer using a computing device.

Example 2 may include the method of example 1 and/or any other exampledisclosed herein, further includes providing illumination through athird optical train configured with brightfield optical components tofocus brightfield illumination toward the one or more features of thesemiconductor specimen, and sensing the field illumination from the oneor more features of the semiconductor specimen using a third CCD sensor,and for which the analyzed data for the one or more features of thesemiconductor specimen includes data captured by the third CCD sensor.

Example 3 may include the method of example 2 and/or any other exampledisclosed herein, for which the semiconductor specimen further includesa blank extreme ultraviolet (EUV) mask and for which the one or morefeatures further includes alignment marks or surface defects on theblank EUV mask.

Example 4 may include the method of example 3 and/or any other exampledisclosed herein, for which the data analyzing for the alignment marksor surface defects on the blank EUV mask provides for comparisons ofstored data for an ideal image for a standardized blank EUV mask.

Example 5 may include the method of example 4 and/or any other exampledisclosed herein, further includes for which the data analyzing includesproducing a combined multi-mode phase contrast, darkfield, andbrightfield representation of the blank EUV mask as a defect map oralignment mark map.

Example 6 may include the method of example 2 and/or any other exampledisclosed herein, for which the semiconductor specimen further includesa blank semiconductor wafer and for which the one or more featuresfurther includes surface defects on the blank semiconductor wafer.

Example 7 may include the method of example 6 and/or any other exampledisclosed herein, for which the data analyzing for surface defects onthe blank semiconductor wafer provides for comparisons with stored datafor an ideal image for a standardized blank semiconductor wafer.

Example 8 may include the method of example 7 and/or any other exampledisclosed herein, for which the data analyzing further includesproducing a combined multi-mode phase contrast, darkfield, brightfieldrepresentation of the blank semiconductor mask as a defect map.

Example 9 may include the method of example 1 and/or any other exampledisclosed herein, for which the providing the semiconductor specimenfurther includes providing an assembled semiconductor device as thesemiconductor specimen for inspection, for which the inspection isperformed upon the completion of designated assembly process steps forthe assembled semiconductor.

Example 10 may include the method of example 1 and/or any other exampledisclosed herein, further includes providing a pre-programmed patternfor automated scanning of surfaces of the semiconductor specimen.

Example 11 provides an inspection system that includes an opticalinspection tool including a stage, a light source, a first optical trainconfigured with phase contrast optical components, a second opticaltrain configured with darkfield optical components, and at least one CCDsensor configured to sense illumination directed from a semiconductorspecimen, a laser interferometer, and a computing device.

Example 12 may include the inspection system of example 11 and/or anyother example disclosed herein, for which the optical inspection toolfurther includes a third optical train configured with brightfieldoptical components.

Example 13 may include the inspection system of example 11 and/or anyother example disclosed herein, for which the first optical trainfurther includes Zernike optical components.

Example 14 may include the inspection system of example 11 and/or anyother example disclosed herein, for which the second optical trainfurther includes Schwarzchild optical components.

Example 15 may include the inspection system of example 11 and/or anyother example disclosed herein, for which the computing device furtherincludes a system control unit, a measurement data analyzer, and a datastorage unit.

Example 16 may include the inspection system of example 11 and/or anyother example disclosed herein, for which the semiconductor specimenfurther includes a blank EUV mask with one or more alignment marksand/or defects or a blank semiconductor wafer with one or more surfacedefects.

Example 17 may include the inspection system of example 11 and/or anyother example disclosed herein, for which the computing device providesan output comprising two dimensional maps with both phase contrast dataand darkfield data.

Example 18 may include the inspection system of example 12 and/or anyother example disclosed herein, for which the computing device providesan output comprising two dimensional maps with combined phase contrastdata, darkfield data, and brightfield data.

Example 19 provides an optical inspection tool including a stage, a deepultraviolet laser emitting 193-nanometer wavelength illumination, and amulti-mode optical system including a first optical train configuredwith phase contrast optical components, a second optical trainconfigured with darkfield optical components, and a third optical trainconfigured with brightfield optical components, and at least one CCDsensor configured to sense illumination directed from a semiconductorspecimen.

Example 20 may include the optical inspection tool of claim 19 and/orany other example disclosed herein, for which the multi-mode opticalsystem further includes a brightfield optical inspection tool that isretrofitted with phase contrast optical components, darkfield opticalcomponents, and phase contrast and darkfield CCD sensors.

The term “comprising” shall be understood to have a broad meaningsimilar to the term “including” and will be understood to imply theinclusion of a stated integer or operation or group of integers oroperations but not the exclusion of any other integer or operation orgroup of integers or operations. This definition also applies tovariations on the term “comprising” such as “comprise” and “comprises”.

The term “coupled” (or “connected”) herein may be understood aselectrically coupled or as mechanically coupled, e.g., attached or fixedor attached, or just in contact without any fixation, and it will beunderstood that both direct coupling or indirect coupling (in otherwords: coupling without direct contact) may be provided.

The terms “and” and “or” herein may be understood to mean “and/or” asincluding either or both of two stated possibilities.

While the present disclosure has been particularly shown and describedwith reference to specific aspects, it should be understood by thoseskilled in the art that various changes in form and detail may be madetherein without departing from the spirit and scope of the presentdisclosure as defined by the appended claims. The scope of the presentdisclosure is thus indicated by the appended claims and all changeswhich come within the meaning and range of equivalency of the claims aretherefore intended to be embraced.

What is claimed is:
 1. An inspection method comprising: providing asemiconductor specimen on a stage for inspection; providing a lightsource to produce illumination; providing illumination through a firstoptical train configured with phase contrast optical components to focusphase contrast illumination toward one or more features of thesemiconductor specimen, and sensing the phase contrast illumination fromthe one or more features of the semiconductor specimen using a firstcharge-coupled device (CCD) sensor; providing illumination through asecond optical train configured with darkfield optical components tofocus darkfield illumination toward the one or more features of thesemiconductor specimen, and sensing the darkfield illumination from theone or more features of the semiconductor specimen using a second CCDsensor; providing position measurements using a laser interferometer;and generating analyzed data for the one or more features of thesemiconductor specimen from data captured by the first and second CCDsensors and laser interferometer using a computing device.
 2. The methodof claim 1, further comprising: providing illumination through a thirdoptical train configured with brightfield optical components to focusbrightfield illumination toward the one or more features of thesemiconductor specimen, and sensing the field illumination from the oneor more features of the semiconductor specimen using a third CCD sensor;and wherein the analyzed data for the one or more features of thesemiconductor specimen includes data captured by the third CCD sensor.3. The method of claim 2, wherein the semiconductor specimen furthercomprises a blank extreme ultraviolet (EUV) mask and wherein the one ormore features further comprises alignment marks or surface defects onthe blank EUV mask.
 4. The method of claim 3, wherein the data analyzingfor the alignment marks or surface defects on the blank EUV maskprovides for comparisons of stored data for an ideal image for astandardized blank EUV mask.
 5. The method of claim 4, wherein the dataanalyzing comprises producing a combined multi-mode phase contrast,darkfield, and brightfield representation of the blank EUV mask as adefect map or alignment mark map.
 6. The method of claim 2, wherein thesemiconductor specimen further comprises a blank semiconductor wafer andwherein the one or more features further comprises surface defects onthe blank semiconductor wafer.
 7. The method of claim 6, wherein thedata analyzing for surface defects on the blank semiconductor waferprovides for comparisons with stored data for an ideal image for astandardized blank semiconductor wafer.
 8. The method of claim 7,wherein the data analyzing further comprises producing a combinedmulti-mode phase contrast, darkfield, brightfield representation of theblank semiconductor mask as a defect map.
 9. The method of claim 1,wherein the providing the semiconductor specimen further comprisesproviding an assembled semiconductor device as the semiconductorspecimen for inspection, wherein the inspection is performed upon thecompletion of designated assembly process steps for the assembledsemiconductor.
 10. The method of claim 1, further comprises providing apre-programmed pattern for automated scanning of a surface of thesemiconductor specimen.
 11. An inspection system comprising: an opticalinspection tool comprising: a stage; a light source; a first opticaltrain configured with phase contrast optical components; a secondoptical train configured with darkfield optical components; and at leastone CCD sensor configured to sense illumination directed from asemiconductor specimen; a laser interferometer; and a computing device.12. The inspection system of claim 11, wherein the optical inspectiontool further comprises a third optical train configured with brightfieldoptical components.
 13. The inspection system of claim 11, wherein thefirst optical train further comprises Zernike optical components. 14.The inspection system of claim 11, wherein the second optical trainfurther comprises Schwarzchild optical components.
 15. The inspectionsystem of claim 11, wherein the computing device further comprises asystem control unit, a measurement data analyzer, and a data storageunit.
 16. The inspection system of claim 11, wherein the semiconductorspecimen further comprises a blank EUV mask with one or more alignmentmarks and/or defects, or a blank semiconductor wafer with one or moresurface defects.
 17. The inspection system of claim 11, wherein thecomputing device provides an output comprising two dimensional maps withboth phase contrast data and darkfield data.
 18. The inspection systemof claim 12, wherein the computing device provides an output comprisingtwo dimensional maps with combined phase contrast data, darkfield data,and brightfield data.
 19. An optical inspection tool comprising: astage; a deep ultraviolet laser emitting 193-nanometer wavelengthillumination; and a multi-mode optical system comprising: a firstoptical train configured with phase contrast optical components; asecond optical train configured with darkfield optical components; and athird optical train configured with brightfield optical components; andat least one CCD sensor configured to sense illumination directed from asemiconductor specimen.
 20. The optical inspection tool of claim 19,wherein the multi-mode optical system further comprises a brightfieldoptical inspection tool that is retrofitted with phase contrast opticalcomponents, darkfield optical components, and phase contrast anddarkfield CCD sensors.